const arr = [1, 2]
const set = new Set()
const map = new Map()
console.log(typeof arr, typeof set, typeof map)  // object

console.log(Object.prototype.toString.call(arr))  // [object Array]
console.log(Object.prototype.toString.call(set))  // [object Set]
console.log(Object.prototype.toString.call(map))  // [object Map]

